This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.

Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.

1wkf

From Proteopedia

(Difference between revisions)

Jump to: navigation, search

Revision as of 16:17, 11 April 2018

TRNA-GUANINE TRANSGLYCOSYLASE

Structural highlights

1wkf is a 1 chain structure with sequence from "achromobacter_anaerobium"_(sic)_shimwell_1937 "achromobacter anaerobium" (sic) shimwell 1937. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Ligands:
Gene:	TGT ("Achromobacter anaerobium" (sic) Shimwell 1937)
Activity:	tRNA-guanine(34) transglycosylase, with EC number 2.4.2.29
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

[TGT_ZYMMO] Exchanges the guanine residue with 7-aminomethyl-7-deazaguanine in tRNAs with GU(N) anticodons (tRNA-Asp, -Asn, -His and -Tyr). After this exchange, a cyclopentendiol moiety is attached to the 7-aminomethyl group of 7-deazaguanine, resulting in the hypermodified nucleoside queuosine (Q) (7-(((4,5-cis-dihydroxy-2-cyclopenten-1-yl)amino)methyl)-7-deazaguanosine).[HAMAP-Rule:MF_00168]

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

Procaryotic tRNA-guanine transglycosylase (TGT) catalyzes the posttranscriptional base exchange of the queuine precursor 7-aminomethyl-7-deazaguanine (preQ1) with the genetically encoded guanine at the wobble position of tRNAs specific for Asn, Asp, His, and Tyr. The X-ray structures of Zymomonas mobilis TGT and of its complex with preQ1 [Romier, C., Reuter, K., Suck, D., & Ficner, R. (1996) EMBO J. 15, 2850-2857] have revealed a specific preQ1 binding pocket and allowed a proposal for tRNA binding and recognition. We have used band-shift experiments in denaturing conditions to study the enzymatic reaction performed by TGT. The presence of shifted protein bands after incubation with tRNA followed by protein denaturation indicates a reaction mechanism involving a covalent intermediate. Inspection of the X-ray structures and comparison of the different procaryotic TGT sequences highlighted the conserved aspartate 102 as the most likely nucleophile. Mutation of this residue into alanine by site-directed mutagenesis leads to an inactive mutant unable to form a covalent intermediate with tRNA, proving that aspartate 102 is the active site nucleophile in TGT. To investigate the recognition of the wobble guanine in the preQ1 binding pocket, we mutated aspartate 156, the major recognition element for preQ1, into alanine and tyrosine. Both mutants are inactive in producing the final product, but the mutant D156A is able to form the covalent intermediate with tRNA in the first step of the reaction mechanism in comparable amounts to wild-type protein. Therefore, the binding of the wobble guanine in the preQ1 binding pocket is required for the cleavage of the glycosidic bond. The three mutants were crystallized and their X-ray structures determined. The mutants display only subtle changes to the wild-type protein, confirming that the observed biochemical results are due to the chemical substitutions rather than structural rearrangements.

Mutagenesis and crystallographic studies of Zymomonas mobilis tRNA-guanine transglycosylase reveal aspartate 102 as the active site nucleophile.,Romier C, Reuter K, Suck D, Ficner R Biochemistry. 1996 Dec 10;35(49):15734-9. PMID:8961936^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Romier C, Reuter K, Suck D, Ficner R. Mutagenesis and crystallographic studies of Zymomonas mobilis tRNA-guanine transglycosylase reveal aspartate 102 as the active site nucleophile. Biochemistry. 1996 Dec 10;35(49):15734-9. PMID:8961936 doi:10.1021/bi962003n

1 Structural highlights
2 Function
3 Evolutionary Conservation
4 Publication Abstract from PubMed
5 See Also
6 References

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "http://52.214.119.220/wiki/index.php/1wkf"

Categories: Ficner, R | Reuter, K | Romier, C | Suck, D | Trna-modifying enzyme

@@ Line 1: / Line 1: @@
 ==TRNA-GUANINE TRANSGLYCOSYLASE==
 <StructureSection load='1wkf' size='340' side='right' caption='[[1wkf]], [[Resolution|resolution]] 2.20&Aring;' scene=''>
@@ Line 6: / Line 7: @@
 <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">TGT ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=542 "Achromobacter anaerobium" (sic) Shimwell 1937])</td></tr>
 <tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/tRNA-guanine(34)_transglycosylase tRNA-guanine(34) transglycosylase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.4.2.29 2.4.2.29] </span></td></tr>
-<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1wkf FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1wkf OCA], [http://pdbe.org/1wkf PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1wkf RCSB], [http://www.ebi.ac.uk/pdbsum/1wkf PDBsum]</span></td></tr>
+<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1wkf FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1wkf OCA], [http://pdbe.org/1wkf PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1wkf RCSB], [http://www.ebi.ac.uk/pdbsum/1wkf PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1wkf ProSAT]</span></td></tr>
 </table>
 == Function ==
@@ Line 14: / Line 15: @@
 Check<jmol>
   <jmolCheckbox>
-    <scriptWhenChecked>select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/wk/1wkf_consurf.spt"</scriptWhenChecked>
+    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/wk/1wkf_consurf.spt"</scriptWhenChecked>
     <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
     <text>to colour the structure by Evolutionary Conservation</text>

1wkf

From Proteopedia

Revision as of 16:17, 11 April 2018

TRNA-GUANINE TRANSGLYCOSYLASE

Structural highlights

Function

Evolutionary Conservation

Publication Abstract from PubMed

See Also

References

Contents

Proteopedia Page Contributors and Editors (what is this?)

Views

Personal tools

Navigation

Search

Toolbox